Combination cancer gene therapy in endostatin and suicide gene for metastatic murine mammary cancers

用含有血管生成抑制基因的非病毒质粒载体的电基因转移在小鼠中进行实验性乳腺癌治疗。体外研究：转染内皮抑素（pEndo）、血管抑素（pAngio）及两者融合基因（pEndo：pAngio）的HUVECs在Matrigels上的小管形成受到抑制。体内研究：实验1。通过用BJMC 3879细胞接种BALB/c小鼠诱导的乳腺肿瘤随后通过每周一次直接注射pEndo、pAngio、pEndo：pAngio或对照载体治疗7周。在实验第1周和之后的整个研究中，观察到pEndo或pEndo：pAngio组的肿瘤体积显著减小。在pAngio组中，仅在第7周观察到肿瘤体积减小。实验2.使用相同的乳腺癌模型，进行pEndo与自杀基因（HSVtk/GCV）的联合治疗。在pEndo、pHSVtk/GGCV和组合组中，肿瘤体积被显著抑制。在联合治疗组中，与各自的单独治疗组相比，肿瘤体积得到进一步抑制。在治疗组中，肺或淋巴结转移也显著减少。然而，在联合治疗组中未观察到对转移的总结性或协同作用。在pEndo或组合组中，肿瘤组织内的微血管密度显著降低。在所有治疗组中也发现DNA合成减少和细胞凋亡增加。此外，在pEndo或组合组中，在其管腔中具有迁移癌细胞的淋巴管的数目被显著抑制。因此，我们得出结论，内皮抑素基因与体内电基因转移可以导致抑制乳腺肿瘤的生长和转移。此外，内皮抑制素与HSVtk/GCV联合治疗进一步抑制肿瘤生长，但未观察到减少转移的累积效应。

Experimental mammary cancer therapy in mice was conducted with electrogene transfer of a non-viral plasmid vector containing angiostatic genes. In vitro study : HUVECs transfected with endostatin (pEndo), angiostatin (pAngio) and both fusion genes (pEndo:pAngio) were inhibited the tubular formation on Matrigels. In vivo study : Experiment 1. Mammary tumors induced by inoculation of BALB/c mice with BJMC3879 cells were subsequently treated by direct injection of pEndo,pAngio,pEndo:pAngio or control vector once a week for 7 weeks. Significantly reduced tumor volumes were observed for the pEndo or pEndo:pAngio groups in experimental week 1 and thereafter throughout the study. In the pAngio group, reduced tumor volume was only observed in week 7. Experiment 2. Using the same mammary cancer model, combination therapy in pEndo with suicide gene (HSVtk/GCV) was conducted. Tumor volumes were significantly suppressed in the pEndo,pHSVtk/GGCV and the combination groups. In the combination group, the tumor volumes were further suppressed as compared with respective alone treatment groups. In therapeutic groups, metastases to lungs or lymph nodes were also significantly decreased. However, summative or synergistic effects were not observed in the combination group on metastases. Microvessel density within tumor tissues was significantly decreased in the pEndo or the combination groups. Decreased DNA synthesis and elevated apoptosis were also found in all therapeutic groups. in addition, numbers of lymphatic vessels with migrating cancer cells in their lumens were significantly inhibited in pEndo or the combination groups. We therefore conclude that endostatin gene with in vivo electrogene transfer can result in suppression of mammary tumor growth and metastases. In addition, endostatin in combination therapy with HSVtk/GCV further suppressed tumor growth but summative effects were not observed on reduction of metastases.